Vascular dilatation balloons on medical devices generally fall into two classes. The first class of vascular dilatation balloons comprises a noncompliant balloon formed from a relatively nondistensible material such as polyethylene terephthalate (PET). Noncompliant balloons exhibit a substantially uniform exterior inflated profile which remains substantially unchanged upon increasing inflation pressures. Noncompliant balloons have been suggested to be advantageous because they allow the introduction of increased inflation pressure to break calcified lesions while retaining a predictable inflation profile thus minimizing damage to the surrounding lumen. Non-limiting examples of noncompliant balloons are disclosed in U.S. Pat. No. 6,200,290 to Burgmeier and Published Application U.S. 2010/0022949 to Eidenschink. Additional examples are commonly known in the art.
The second class of vascular dilatation balloons comprises compliant balloons. Compliant balloons expand in diameter upon increased inflation pressure. A problem with compliant balloons has been that upon inflation within a lesion, the balloon inflates unevenly around the plaque to form an hour glass type shape. The uneven inflation of the compliant balloon can result in damage to the lumen as well as failure to alleviate the stenosis. Non-limiting examples of compliant balloons are disclosed in U.S. Pat. No. 6,120,477 to Campbell et al. and U.S. Pat. No. 6,890,395 to Simhambhatla, each of which is incorporated by reference herein in its entirety. Additional examples are commonly known in the art.
It is not uncommon with either types of balloons to have some difficulty in properly positioning the balloon, which are usually located on the distal ends of catheters, within the region of the lesion of a patient's artery or other body lumen or, if properly positioned within the lesion, to have difficulty in maintaining the position of the inflatable member or balloon within the lesion during balloon inflation.
What is needed is a balloon which can be preferentially inflated in different sections to better control the position of the balloon and to provide a more uniform pressure against the lesion during the dilatation. In addition, there is a need for a balloon that can be preferentially inflated in different sections to more precisely expand an interventional device at the site of a lesion. Although U.S. Pat. No. 5,470,313 and U.S. Pat. No. 5,843,116 disclose focalized intraluminal balloons with variable inflation zones or regions, the present invention allows any type of balloon to be preferentially inflated at different sections without modifying the balloon or delivery catheter.